/Engine/Plugins/Experimental/MeshModelingToolsetExp/Source/MeshModelingToolsExp/Public/MeshVertexPaintTool.h
Fill all Vertex Colors with the Color (1,1,1,1). Current Channel Filter still applies.
[UFUNCTION](Programming/UnrealArchitecture/Reference/Functions)(CallInEditor, Category=QuickActions, Meta=(DisplayPriority=14)) void FillWhite()